1. Field of the Invention
This invention relates generally to medical instruments, and more particularly, to an instrument for endoscopically manipulating organs in the interior of the body.
2. Description of the Prior Art
Instruments utilizing one or more spreading member(s) at the distal end thereof are used in particular in endoscopic procedures, e.g. in the abdominal cavity, to manipulate organs or other internal parts of the body, generally in order to bring the latter into a position and to maintain them in such a position that they do not cover or conceal the area to be examined or treated. Such instruments are subject to special requirements, since they should be as slender and smooth as possible on the one hand for the purpose of insertion into the body cavity and, on the other hand, should. provide the best possible hold inside the body cavity. For this purpose, the instruments must be able to spread out over the largest possible surface area and also to transmit sufficient forces in this position, for example, to hold back a larger organ reliably. Further, the instruments must be constructed so as to exclude the risk of injury to a great extent, also in the spread out state.
An instrument of the generic type is known from DE 40 21 153 A1. This organ manipulator has proven successful in practical use. In particular, it satisfies the above-mentioned requirements to a great extent. This manipulator, which can be spread out in various positions, is generally used as a spatula, i.e. forces can be applied substantially only transversely to the surface spread out by the spreading members and, to a very limited extent, compressive forces may be applied in the direction from the proximal end to the distal end of the instrument. Essentially, the spreading members of this manipulator lie substantially in a common plane while they are in the "spread out" state. Disadvantageously, however, the organ to be manipulated typically has a spatially curved surface. Accordingly, high compressive loading may occur at points on the organ when the flat spreading members act on a sharply curved region of the organ. Additionally, it may not be possible to prevent the organ from slipping off the manipulator. Such slippage is highly undesirable and dangerous particularly when therapeutic procedures are in progress. Moreover, while it may be desirable in some applications to push the organ in one direction or the other, the conditions under which this is possible with the manipulator described above are very limited due to the risk of slippage.
An optical tissue hook is disclosed in DE 41 25 806 A1. This device has a shaft with a plurality of spreading elements which elements are arranged so as to be displaceable axially in the shaft. The spreading elements are pretensioned by means of a spring and have a double bend at the distal end. A hollow organ to be treated can be fixed and visually monitored by means of these spreading elements. This instrument is intended and suited exclusively for fixing a hollow organ at the abdominal wall, specifically by means of a clamping action between parts of the instrument. This instrument is not capable of the lateral displacement of organs mentioned above, e.g. for holding an organ away from a determined region of the body cavity.
Yet another endoscopic organ manipulator is disclosed in DE 37 09 706 A1. This manipulator has three resiliently elastic wires with spherical elements at their distal ends. These wires are pretensioned transversely to the longitudinal direction of the instrument in such a way that they spring out laterally when moved out of a sleeve tube so as to spread out in a spatial formation. This manipulator has the considerable disadvantage that it can exert only comparatively limited forces, since the wires deflect when loaded due to their springing action. The instrument is therefore unsuited for the area of use mentioned initially above.
It is therefore an object of the present invention to provide an instrument which avoids the aforementioned disadvantages associated with the prior art.
It is a further object of the present invention to provide an instrument which retains the characteristics and possibilities of use mentioned above and which also enables reliable lateral guidance of an organ, i.e. transversely to the axis of the instrument, without the risk of slippage.
It is yet another object of the present invention to provide an instrument which can also exert pulling forces on the organ, at least proportionally.